The related application Ser. No. 506,547 filed Sept. 16, 1974 for "Leak Testing Method and Apparatus for Tubular members and Packer Means Therefor" discloses a method and structural arrangement of an external tester which may be maintained in a position about a tubular member for the testing of a certain portion of the tubular member, such as the connection means thereof, for defects by the use of fluid under pressure. The method and structural arrangement of the external tester disclosed in such application Ser. No. 506,547 includes at least one annular seal capable of radial movement inwardly toward the tubular member for sealingly engaging with the tubular member. The annular seal means disclosed in application Ser. No. 506,547 comprises an annular elastomer body having surfaces extending toward the tubular member and back-up means on such surfaces for aiding in inhibiting extrusion of the elastomer body when the elastomer body is urged into sealing engagement with the tubular member.
In the seal means disclosed in application Ser. No. 506,547, a plurality of back-up means are mounted on the inwardly extending surfaces of the elastomer body at selected spaced arcuate positions. Each of such back-up means is tapered and spaced from the adjacent back-up means whereby when the elastomer body is moved radially inwardly toward the tubular member, the back-up means are moved radially inwardly toward the tubular member and are moved annularly relative to each of the other back-up means.
It has been found that when the annular seal moves radially inwardly a sufficient distance to cause each of the back-up means to contact its two adjacent back-up means, there is formed a continuous barrier which aids significantly in inhibiting extrusion of the elastomer body. However, whenever the diameter of the tubular member and the shape of the annular seal means are such that each of the back-up means does not contact its two adjacent back-up means when the seal means sealingly engages the tubular member, it has been found that extrusion of the elastomer body still occurs. This is because there exist slight spaces between the adjacent back-up means, and the elastomer body, which takes on the characteristics of a liquid when subjected to the enormous pressures involved in the external testing of pipe, will extrude into such spaces. This extrusion causes damage and wear and tear on the annular seal and shortens the life of the seal.
It is an object of this invention to provide an improved annular seal for engaging a tubular member, such seal having an annular elastomer body capable of moving radially inwardly toward the tubular member responsive to a selected fluid pressure being supplied to the outer circumferential surface of the body and having an interlocking reinforcing means associated with the inner annular surface of the elastomer body, which reinforcing means provides a continuous reinforcing barrier inhibiting undesirable extrusion of the elastomer body inwardly toward the tubular member irrespective of the degree of closure of the annular seal.
It is an object of this invention to provide an improved annular seal for use in a testing apparatus for externally testing a portion of a tubular member in which the annular seal sealingly engages with the tubular member responsive to selected fluid pressure supplied to its outer circumferential surface, such annular seal including reinforcing means comprising a plurality of interlocking segments presenting a continuous reinforcing barrier for inhibiting extrusion of the elastomer body inwardly toward the tubular member between adjacent segments irrespective of the degree of closure of the annular seal.
The invention itself, as well as additional objects and advantages thereof, will become readily apparent from the following description when read in connection with the accompanying drawings, in which like numerals represent like parts: